Electronic devices, for example, smartphones, tablet personal computers (PCs), laptop computers, or the like are used in a variety of fields due to convenience of use and easy portability. Recently, there has been a growing interest in an external device operatively connected with an electronic device, for example, an accessory device (e.g., a head-mounted display (HMD) device, a docking station, or the like). Also, the accessory device may be connected with an auxiliary accessory device, for example, a power supply.
An electronic device, for example, an HMD device may be used by being operatively connected with a mobile terminal and the like. In this case, the HMD device may receive power from the mobile terminal. Also, the HMD device may be connected with an auxiliary accessory device, for example, a power supply. In this case, the HMD device may be used by receiving power from the power supply.
If the HMD device which is used by receiving power from the power supply is disconnected from the power supply, the HMD device may be temporarily powered off. For example, before a mobile terminal recognizes that the HMD device is disconnected from the power supply and supplies power to the HMD device, the HMD device may be temporarily powered off. Such temporal power-off is distraction from user experience. Thus, in any case, it is necessary to continue maintaining power of the HMD device which is in use.